The subject matter disclosed herein relates generally to rotary wing aircraft, and in particular to tracking blades of a rotary wing aircraft.
Conventional methods for measuring blade track use optical camera equipment sensitive to visible and electromagnetic light wave spectra to detect contrast differences as blades block the background sky. The time difference between the leading and trailing edges of each blade pass is used to calculate blade track as well as lead/lag motions. Some of the shortcomings of conventional methods are the lack of reliable timing triggers due to low contrast differences between light colored blades and the background sky, along with increased rotor speed with reduced blade chord width. The low detection of lighter color blades works against the process of gathering blade track data. In addition, the blade track is only measured at one azimuthal location in the blade path above the optical camera.